1. Technical Field
The present invention relates generally to an over-the-highway truck or tractor vehicle having a frame and a cab. In particular, the present invention relates to a system for suspending the cab relative to the frame and for damping relative movement between them.
2. Description of the Prior Art
A conventional over-the-highway truck or tractor vehicle includes a frame for supporting an operator's cab. The frame is typically supported by load springs extending between the frame and the axles of the vehicle. Due to the relatively large load that such a vehicle transports, the load springs have a relatively high spring rate. Thus, any uneven road surface that the vehicle is operating over or any imbalance or untrueness of the tire and wheel assemblies of the vehicle results in a shock or vibration that is transmitted to the operator's cab.
Cab suspensions have been developed which include cab springs and dampers located between the vehicle frame and operator's cab to minimize transmission of such shock and vibration to the cab. Some developments in cab suspensions locate at least part of the suspension system near the rear of the cab and close to the center of gravity of the vehicle.